7 trials tracked · 2 active · last refreshed 2026-08-10
Ambroxol is a decades-old, cheap generic drug (sold over-the-counter in many countries as a cough/mucolytic) being repurposed for a specific genetic subgroup of Parkinson's — patients who carry a GBA1 mutation, which impairs a cellular enzyme ambroxol happens to boost. The bet is that raising that enzyme's activity could slow disease progression in exactly this subgroup, not in Parkinson's broadly.
Of the 7 trials tracked, results have been mixed and mostly still maturing: a completed Phase II trial reported the drug reached the brain and engaged its target safely without yet showing clear symptomatic benefit, and a Phase III trial is now recruiting to test whether it actually slows progression over a longer follow-up. Several other smaller trials in the same GBA-Parkinson's space are still marked unknown status rather than clearly active or closed out.
Click a row for what it's testing, where, and how many participants.
| NCT ID | Title | Phase | Status | Started | |
|---|---|---|---|---|---|
| ▸ | NCT05778617 | Ambroxol to Slow Progression in Parkinson Disease | Phase III | Recruiting | 2025-02-25 |
This is a UK only clinical trial in patients with Parkinson's disease (PD) of a drug called ambroxol hydrochloride, which is an already licensed drug for the treatment of respiratory conditions (such as a common cold) in many European countries. The aim of this trial is to find out whether ambroxol hydrochloride can slow down the progression of Parkinson's disease and to evaluate it's safety and tolerability. Enrollment 330 (estimated) Sites 15 across 1 country Countries United Kingdom Sponsor University College, London Primary outcome: Change in Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Parts I- III score from baseline to Week 104. | |||||
| ▸ | NCT06193421 | High-Dose Ambroxol in GBA1-Related Parkinson | Phase I, Phase II | Unknown | 2023-10-24 |
Parkinson's disease (PD), affecting 10 million people globally, lacks a cure, and current therapies only manage symptoms. A link between Gaucher disease (GD) and PD, particularly in carriers of glucocerebrosidase (GBA1) mutations, has sparked interest in developing new drugs. Despite pharmaceutical companies focusing on formulations, progress is slow. Agyany, with decades of experience in GD research, plans clinical trials using existing generic drugs for GBA-related PD and idiopathic PD. Their approach targets the misfolded enzyme glucocerebrosidase with pharmacological chaperons, inspired by success in GD using ambroxol. The strategy aims to provide a quicker path to novel therapeutic options for PD. Enrollment 40 (estimated) Sites 1 across 1 country Countries Israel Sponsor Agyany Pharma LTD Primary outcome: Number of Participants With Treatment-Emergent Adverse Events (TEAEs), and Treatment-Emergent Serious Adverse Events (TESAEs) | |||||
| ▸ | NCT05830396 | GRoningen Early-PD Ambroxol Treatment | Phase II, Phase III | Unknown | 2023-05 |
The most common genetic risk factor for Parkinson's Disease is a heterozygous mutation of the GBA1 gene, encoding the lysosomal enzyme glucocerebrosidase (GCase). Reduced GCase activity is associated with aggregation of the protein alpha synucleine (aSyn) in the central nervous system, which is related to the pathological cause of PD. Ambroxol is a mucolytic expectorant that appears to facilitate the refolding of the misfolded GBA protein thats acts as a chaperone for GCase. This randomized placebo-controlled trial aims to investigate the disease-modifying properties of ambroxol in PD patients with a GBA1-mutation. Patients will undergo motor and cognitive tests, as well as imaging and blood tests. Enrollment 80 (estimated) Sites 1 across 1 country Countries Netherlands Sponsor University Medical Center Groningen Primary outcome: MDS-UPDRS3 motor scale | |||||
| ▸ | NCT05287503 | Ambroxol as a Disease-modifying Treatment in GBA-PD | Phase II | Completed | 2022-03-09 |
The present multicenter, randomized, double-blind, placebo-controlled clinical trial will investigate whether the prolonged administration of high-dose oral Ambroxol over 52 weeks is safe, tolerable, able to change Glucocerebrosidase enzyme activity and alpha-synuclein levels in the central nervous system and, ultimately, to reduce the progression of cognitive decline and motor disability in 60 individuals with Parkinson's disease with mutations of the glucocerebrosidase gene (GBA1; OMIM 606463). Participants will undergo clinical, biomarker blood and cerebrospinal fluid analysis, neuropsychological, neuroimaging assessment throughout the course of the study. Enrollment 65 (actual) Sites 3 across 1 country Countries Italy Sponsor Fondazione I.R.C.C.S. Istituto Neurologico Carlo Besta Primary outcome: Change from baseline in Montreal Cognitive Assessment score | |||||
| ▸ | NCT04388969 | World Data on Ambroxol for Patients With GD and GBA Related PD | N/A | Recruiting | 2020-05-06 |
Ambroxol hydrochloride is an oral mucolytic drug available over-the-counter for many years as cough medicine. In 2009 it was found to also act as a pharmacological chaperone (PC) for mutant glucocerebrosidase, albeit in a several-fold higher dose. Unfortunately, due to its low cost, there have been no pharma-driven clinical trials to establish the use of ambroxol. Thus, data are needed on the safety and efficacy of ambroxol for patients with Gaucher disease (GD). Enrollment 300 (estimated) Sites 3 across 1 country Countries Israel Sponsor Shaare Zedek Medical Center Primary outcome: Establishing a registry to be used as a reference for patients,parents and physicians, who consider using Ambroxol | |||||
| ▸ | NCT02941822 | Ambroxol in Disease Modification in Parkinson Disease | Phase II | Completed | 2016-12 |
This study will evaluate the safety, tolerability and pharmacodynamics of ambroxol in participants with Parkinson Disease. Participants will administer ambroxol at five dose levels and will undergo clinical assessments, lumbar punctures, venepuncture, biomarker blood analysis and cognitive assessment throughout the course of the study. Enrollment 23 (actual) Sites 1 across 1 country Countries United Kingdom Sponsor University College, London Primary outcome: Glucocerebrosidase and ambroxol levels in blood and cerebrospinal fluid | |||||
| ▸ | NCT02914366 | Ambroxol as a Treatment for Parkinson's Disease Dementia | Phase II | Unknown | 2015-11 |
The present study will test the hypothesis that the medication Ambroxol is safe and well tolerated and will improve cognitive and motor symptoms of Parkinson's Disease Dementia (PDD). Ambroxol has been shown to raise the levels of the enzyme beta-glucocerebrosidase resulting in lower the levels of the protein alpha-synuclein, both of which have been shown to improve cognition in mouse models. This will be a 52 week trial of Ambroxol in 75 individuals with PDD. Participants will undergo clinical, neuropsychological and neuroimaging assessment throughout the study to assess changes. Enrollment 55 (actual) Sites 1 across 1 country Countries Canada Sponsor London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's Primary outcome: Changes in the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) | |||||
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